Boss Gary Johnson said: "We had to do a little bit of negotiating with Fulham today and sometimes that doesn't always happen when you were hoping it was.
"We had fingers crossed because we don't want to lose Dan Burn and Dan Burn doesn't want to lose us so the deal was done and he will stay on a youth loan until he's over 21.
"At that point if we do manage to get anywhere near the playoffs then touchwood we can do another deal with Fulham for an emergency loan for that period of time.
"His long term future for this season is with us, which is fantastic and we appreciate Fulham's thoughts. I think they're happy as well that he's happy and that's the main thing."